Tuning devices are important components in a variety of electrical apparatuses such as radiofrequency (RF) and microwave devices, power amplifiers, mixers, and antenna systems. The tuning device is used to adjust the propagation characteristics (e.g., the amplitude or phase at a given frequency) of the electrical signal traveling through components of the apparatus. Examples of such tuning devices include hybrid couplers, RF-tuning networks, resonance filters and tunable antennas. A common feature in all of these forms of tuning devices is that moveable mechanical tuning components are used to adjust the signal's properties.
One problem with the use of moveable mechanical tuning components is that they wear out over time. Repeated use can cause the moving components to fail, resulting in a decrease in the lifetime of the apparatus that the tuning device operates on. Another problem is that moveable components that are not used frequently can become stuck or fused together, resulting in their failure when pressed into use. Still another problem is that the position of a moveable tuning component can be inadvertently changed, due to the motion or vibration of the apparatus. This, in turn, can cause de-tuning of a previously tuned signal. Moreover, the problem of mechanical wear or sticking are exacerbated as the dimensions of the moveable components are scaled down. Additionally, the manufacturing processes associated with integrating moveable micromechanical components into increasingly smaller devices have increased complexity and cost.